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Is hydration of alkenes nucleophillic addition?

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Original post by Isabella~
Is hydration of alkenes nucleophillic addition?

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Electrophilic
Original post by TeachChemistry
Electrophilic




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How come, isn't water a nucleophile?
It can be as it can donate a lone pair but it can also be polarised when approaching Alkene double bond(high negative density because 4 e-) and a species with a + or partially +ve region is a electrophile

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Original post by Isabella~
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How come, isn't water a nucleophile?


It can be as it can donate a lone pair but it can also be polarised when approaching Alkene double bond(high negative density because 4 e-)
and a species with a + or partially +ve region is a electrophile

My mistake the hydrogen is already partially polarised(no need for polarisation) due to difference in electronegativity. It's still attracted to double bond hence water is a electrophile
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(edited 8 years ago)
Original post by Isabella~
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How come, isn't water a nucleophile?


If you review the mechanism for reaction with water you will see the first step is reaction of the double bond with an H on the water. By virtue of electronegativity difference between O and H, the H is delta positive. The mechanism is described as electrophilic addition.
*URGENT ANSWER NEEDED PLEASE*

For anyone that did the chemistry unit 1 Edexcel test last friday, can someone please tell me if, for the question where we had to identify the errors on the drawing of the mechanism, we were supposed to JUST identify the errors or identify the errors AND state how they would be corrected? The question was 3 marks but I'm doing this unit 2 paper from last year with a similar question also worth 3 marks but we have to say how to correct it as well for this one so I'm kinda worried :/

THANK YOU :smile:
hey, im doing OCR AS Chemistry A, and i was wondering if anyone could help me out:colondollar:
im struggling to understand catalytic converters:confused: i was away for the lesson and the sheets the teacher gave me dont really make any sense,
thank you, kirsten :smile:
Original post by _kirstxn
hey, im doing OCR AS Chemistry A, and i was wondering if anyone could help me out:colondollar:
im struggling to understand catalytic converters:confused: i was away for the lesson and the sheets the teacher gave me dont really make any sense,
thank you, kirsten :smile:


There's not much to know here. Look at textbook p.231 and specification p. 36. What do you not understand in particular?
Reply 3169
Hey I am doing OCR AS can anyone tell me the mechanisms i need to know for unit 2?
Original post by AH5223
Hey I am doing OCR AS can anyone tell me the mechanisms i need to know for unit 2?


Electrophilic addition
Nucleophilic substitution
Free radical substitution
Original post by TeachChemistry
There's not much to know here. Look at textbook p.231 and specification p. 36. What do you not understand in particular?


theres a question in the textbook on p.231 "How are harmful Nox and CO formed in a car engine?" i feel like i know the basics of the information but im a bit 'iffy' on how to go about answering it
Reply 3172
Original post by TeachChemistry
Electrophilic addition
Nucleophilic substitution
Free radical substitution


Thanks, i find them so confusing
Original post by _kirstxn
theres a question in the textbook on p.231 "How are harmful Nox and CO formed in a car engine?" i feel like i know the basics of the information but im a bit 'iffy' on how to go about answering it


Try to answer it then check how you did vs. the p. 255 answer
Original post by _kirstxn
theres a question in the textbook on p.231 "How are harmful Nox and CO formed in a car engine?" i feel like i know the basics of the information but im a bit 'iffy' on how to go about answering it


Isn't it with the heterogeneous catalyst - adsorption, chemical reaction (bonds broken), desorption?
This is the mark scheme for 3)b), can someone explain why Concentrated H2SO4 is wrong? AQA AS

Original post by LibertyMan
This is the mark scheme for 3)b), can someone explain why Concentrated H2SO4 is wrong? AQA AS



Concentrated H2SO4 reacts to produce HCl etc which can't be used to distinguish BaCl2 and MgCl2. You'd use H2SO4 conc to distinguish between the anion in two halides

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Original post by C0balt
Concentrated H2SO4 reacts to produce HCl etc which can't be used to distinguish BaCl2 and MgCl2. You'd use H2SO4 conc to distinguish between the anion in two halides

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What would you use?

:frown:
I never understand PPM questions, can anyone explain it to me?

Calculate the concentration of ozone in the sample of air in units of parts per million (ppm) by volume.

I have the volume of ozone, measured in m^3, present in the original sample of air which is 4.743x10-6

Thanks!

(AS Chemistry Edexcel)
Could someone please explain how to work out enthaply combustion and formation & alsowhat are the main equations and info I need to know for green chemistry
Thanks a lot x

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